Error working with Jackson library post-obfuscation using Proguard
It's not obvious from the stack trace, but Jackson needs some annotations, which ProGuard removes by default. Cfr. ProGuard manual > Examples > Processing annotations:
-keepattributes *Annotation*,EnclosingMethodFurthermore, as the ominous package name 'org.codehaus.jackson.map.introspect' suggests, Jackson performs introspection on parsed classes to find getters and setters. Without knowing any better, ProGuard may be removing or renaming these, because your code might not use them explictly. You may have to keep them explicitly, e.g.:
-keep public class mydatapackage.** { public void set*(***); public *** get*();}